Sympathetic or concussion firing device



July 12, 1955 Mac-ADAMS 2,712,790

SYMPATHETIC OR CONCUSSION FIRING DEVICE Filed Dec. 20, 1951 INVENTOR .JESSE EDWARD MACADAMS (DECEASED) BY ADMINISTRATOR J. EDWIN HUTCHINSON B I E- Y ATTORNEYS SYMPATHETIC on coNcUssroN FIRING DEVICE .l'esse Edward MacAdams, deceased, late of Cheverly,

MIL, by J. Edwin Hutchinson, admimstrator, Hyattsviile,Md.

Application December 20, 1951, Serial No. 262,643

\ 6 Claims. (Cl. 102-70) (Granted under Title 35, U. S. Code (1952), see. 266) This invention relates to improvements in demolition firing devices, its underlying characteristic being the sympathetic and substantially simultaneous explosion of any number of explosive charges fitted with the firing device, distributed over an aquatic field of any chosen area, not connected with each other or with any central timing mechanism and adapted to be set 015, for instance, by the explosion in the midst of the mined field of an ordinary military projectile, fired from some remote point.

Stated in other words, a stretch of water may be mined, as in amphibious warfare, with either a large or small number of isolated explosive charges equipped with the instant firing device, and after the array of firing devices has become armed by action of the water the explosion of a powder or other charge in proximity to the mined area will propagate a high velocity shock wave that will automatically set off all of the firing devices and in consequence the respective explosive charges substantially simultaneously.

Advantage is taken of the special property of potassium carbonyl (KzCzOz) of exploding on contact with water. If a pellet of potassium carbonyl be placed near a shocksensitive substance, properly followed by a booster and an explosive charge, and at the end of a desired delay water be admitted to the carbonyl, initiation will ensue with the movement of a single mechanical part.

The ignition of potassium in the presence of water is known, as is also its segregation from contact with water, both features appearing in the U. S. patent to Harold L. Hunt for Bomb, 2,328,277 of August 31, 1943. The structure of that patent is contrived solely for aboveground use so that it can be stepped upon or ridden over by a vehicle. But it has no arming means as herein outlined, nor is it adapted to be set oil by a high velocity shock wave.

The embodiment of these principles in the instant firing I device establishes as one of the objects of the invention the provision of a firing device contrived to be armed by the action of ambient water and later detonated by the action of the same water after the shattering of a breakable disc by a near-by explosion.

Another object of the invention is to provide a firing device which is rugged enough to be safe and virtually impossible to fire accidentally when out of its operating element, yet is sensitive enough to work in its operating element when subjected to a shock impulse of any established energy.

A further object of the invention is to provide a concussion-operated firing device in which is avoided dependence upon any moving part to detonate it after it has once been placed in the water for operation.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 is a perspective view, partly in section, showing 2,7123% Patented July 12, 1%55 the firing device in relation to the demolition block which it is intended to explode, and

Fig. 2 is a central, longitudinal section of the firing device.

In Fig. 1 the demolition block 10 is adapted to be exploded by the firing device 11. The latter constitutes the invention, and it may be used in conjunction with any explosive that can be fitted with an activator well such as 12 to receive it. In the illustration, the well 12 has a thread course 13 into which the nipple 14 is screwed.

This nipple projects backwardly from the body 16 of the device. The body is hollow, defining a chamber 17. The chamber contains a quantity of coarse silica gel 18, of comparable desiccant, for the purpose of absorbing any trace of moisture that might enter with an inseepage of air. An ampoule 19 of potassium carbonyl and its metal holder 20 are embedded in the silica gel. If and when water reaches the potassium carbonyl, an explosion follows, setting off the percussion cap 22, the blasting cap 23, the Tetryl booster 24 and, finally, the Tetrytol explosive 25 which constitutes most of the block 10.

Before dropping the block it and its attached firing device 11 overboard a wrench 25 is used to drive the crusher screw 28 inward. The pressure on the ampoule between the point of the screw at one end and the point of an anvil 29 at the opposite end fractures the ampoule to release the potassium carbonyl. The latter occupies available space in the chamber 17 in waiting for contact by water from the outside.

A tube 30 is screwed into the threaded counterbore 31 of the otherwise open end of the chamber 17. The tube follows a ring 32 which is screwed into the thread course first. This ring retains a breakable disc 34 which is marginally supported by gaskets 35. A disc 36 of soluble material, for instance a cake of salt or sugar, closes the outer end of the tube, being inset as shown. This disc is a. timing device, and the time taken in dissolving a hole through it will denote the period between the safe and armed conditions of the firing device. A waterproof film 37 normally covers the disc 36 to protect it from premature solution.

The operation is as follows. The timing device 11,

manifestly, is screwed into the well 12 of the block 10 so as to comprise an explosive unit. Any desired number of such units is distributed over an underwater area desired to be cleared. Before dropping each unit overboard, the waterproof film 37 is stripped oil, exposing the disc 36 for the subsequent action of the seawater. The ampoule 19 is crushed by operation of the wrench 26.

Arming of the firing device is accomplished when water enters the tube 36 either by dissolving a hole through the disc 36 or dissolving the disc entirely. The water then touches the disc 34. From now on any shock that will fracture this disc will allow water to contact the carbonyl, which will then explode and initiate the firing train. Such a shock is derived from a military projectile exploded in proximity to any one of the units. From there on the remainder of the units explode in chain sequence but so quickly that the explosive effect is simultaneous.

The specific mode of use described herein is only one illustration. The explosive units do not have to be sown in seawater to be effective. They can be distributed over marshy terrain or equivalent places where there is enough water first to dissolve the disc 36, second to combine with the carbonyl when an explosion shatters the disc 34.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or for the Government of the United States ing thereon and received through said water when said disc is exposed to the water thereby to expose the substance to the water, and a water soluble disc disposed within and sealed to said body for preventing exposure of said frangible disc to said shock wave until the soluble disc has been dissolved by said water.

2. A firing device comprising a body adapted to be deposited in a location of ambient water, an ampoule in the body containing a substance subject to explosion upon contact therewith by the water, crusher means operable before depositing the body to release said substance into the body, a frangible disc segregating said substance, being shatterable by impingement thereon of a shock wave'to expose the substance to the then entering water, and a water soluble disc disposed within and sealed to said body for preventing exposure of said frangible disc to said shock wave until the soluble disc is dissolved by said water.

3. A firing device comprising a body adapted to be deposited in a location of ambient water, an ampoule in the body containing a substance subject to explosion upon contact therewith by the water, crusher means operable before depositing the body to release said substance into the body, a soluble disc disposed within and sealed to said body for excluding water from inside the body but being subject to solution to admit the water and establish an armed condition when said soluble disc has been exposed to said water for a predetermined period of time, and a frangible disc disposed within and sealed to said body in spaced relation with respect to said soluble disc for segregating said substance, said frangible disc being shatterable by impingement thereon of a shock wave to expose the substance to the admitted water.

4. A firing device comprising a body having a chamber and adapted to be deposited in a location of ambient water, an ampoule in the chamber containing a substance subject to explosion upon contact therewith by the Water, crusher means manually operable before depositing the body to release said substance into the chamber, a filling of coarse desiccant in the chamber to absorb incipient moisture prior to said release of the substance, a frangible disc confining and sealing the desiccant within said chamber, said frangible disc being shatterable by impingement thereon of a shock wave toexpose the substance to the water, and a water soluble disc disposed within and sealed to said body for preventing exposure of said frangible disc to said shock wave until the solution of the disc by the water.

5. A firing device comprising a body having a chamber and adapted to be deposited in a location of ambient water, a frangible disc in sealing engagement with said body and shatterable by impingement thereon of a shock wave and closingthe only available open end of the chamber, a tube threaded in said open end in abutting engagement with the frangible disc for maintaining the frangible disc in sealing engagement with the body, a water-soluble disc inset in the tube in sealing engagement with said body and spaced from said frangible disc for excluding the ambient .water from said chamber but dissolving to expose the frangible disc to the water when the soluble disc has been exposed to said water for a predetermined period of time, and a substance in the chamber, being subject to explosion upon contact therewith by the water admitted by the shattering of the frangible disc.

6. A firing device comprising a body adapted to be deposited in a location of ambient water, a substance contained in the body, being subject to explosion upon contact therewith by the water, frangible means in sealing engagement with said body for sealing and confining said substance within said body, said frangible means being shatterable by an impinging shock wave of high velocity, and timing means disposed within and sealed to said body for temporarily shutting the frangible disc off from access to the exterior, said timing means being disintegrable by the water for admittance of the water to the frangible disc and immediate access of the shock Wave to said disc.

References Cited in the file of this patent UNITED STATES PATENTS 

